e.2 W. B. Rogers on Sonorous Flames. 
no audible effect and would seem quite inadequate to excite in 
the column any but the very feeblest vibration. Admitting 
however that these extremely faint vibrations of the air may 
contribute somewhat to the result, it can hardly be doubted that 
the main influence by which the movement of the jet produces 
the effect in question is by causing § so be a a mixture of the ad- 
the flame is well exemplified by the following experiment. 
Fastening a jet-pipe, some twelve inches in lengthy. into the 
end of the long flexible tube through which the gas is supplied, 
and holding it erect by a — a little below the insertion so 
that we can readily cause it to vibrate, we ignite the gas and ad- 
just it to form a slender flame about an inch long. If now the 
flame be moved from side to side through a distance of five or 
six inches, at a moderately rapid rate, it will assume, according 
1 known visual law, the appearance of a continuous arch 
nitish light, retaining at the extremities the whole height of 
ationary flame, but growing narrower from either side to- 
he middle. In these conditions the flame is entirely norse- 
less. As we gradually increase the speed of the vibrations, the 
arch, at a certain velocity, suddenly breaks in the middle, where 
nt bluish flame takes the place of the usual whitish light, 
ar | at the same instant a sharp novse is heard due to the pete i 
- of the explosive mixture at this part of the vibration. It 
t be 
feeclved idly in a circle the white Tigh it ventrely dis 
and the. =e of bluish flame which results gives fort 
but not distinctly musical sound. When made in a dark 
se sinple OS were found to be unexpectedly 
arly observed when a flame of any kind is 
Ny when the air is forced into and 
e case of the jet of was 
